1. Field of the Invention
The present invention relates to navigation devices such as GPS receivers. More particularly, the invention relates to a system and method for wirelessly linking a GPS device with a portable electronic device to provide the portable electronic device with GPS functions.
2. Description of the Prior Art
The global positioning system (GPS) is an electronic satellite navigation system which permits users to determine their position with respect to the Earth. GPS receivers and other navigational devices continue to grow in popularity and are used in many applications, including recreational activities and automobile and marine navigation.
GPS receivers detect and decode signals from a number of satellites orbiting the Earth. The signals from each of these satellites indicate the position of the satellite and the time at which the signals were sent. To decode the satellite signals, known as spread spectrum signals, and thereby calculate desired position and navigational data, a GPS receiver must first “find” or acquire the signals emitted from a minimum number of satellites. Once the receiver is “locked on” to the spread spectrum signals, the user's global position and other navigational data (e.g., velocity of movement) can be calculated.
A typical GPS unit includes (along with other components) a GPS receiver which receives the satellite signals, resident memory in which cartographic data and other location information may be stored, a processor and associated GPS software for determining the location of the unit as a function of the received satellite signals and for accessing and processing data and information in the memory, and a display for displaying the information along with an indication of the unit's location. The resident memory may be integral with the processor, memory chips coupled with the processor, or may include plug-in memory modules that fit within corresponding memory slots in the receiver. The processor retrieves information from the memory, for example, to display maps and routing instructions to permit a user of the GPS receiver to navigate to a desired location.
Portable electronic devices such as cellular telephones, personal digital assistants (PDAs), portable computers, and short range radios, also remain popular. Many GPS users often carry one or more of these portable electronic devices along with a GPS receiver so that they can communicate with others or perform other activities provided by the portable electronic device while navigating with the GPS receiver. Unfortunately, carrying and using multiple devices can be cumbersome, especially while driving, hiking, or performing other activities requiring mental concentration or physical exertion.
In recent years, attempts have been made to combine GPS receivers and other types of portable electronic devices to lessen the number of devices that need to be carried and used. For example, many PDAs and cellular phones now come equipped with onboard GPS receivers so that the location of the PDA or phone may be determined and displayed along with other information. Unfortunately, such combined devices are relatively expensive and complicated to use. Many people are therefore reluctant to purchase such combined units because they may rarely need to use the GPS functions and do not want their PDA or phone cluttered with controls for rarely-used functions. Moreover, such combined units require that some of the processing power normally reserved for the cellular phone or PDA be used for GPS functions, thus requiring either more memory and more powerful processors or longer processing times. Another limitation of such combined units is that they only combine GPS functions with a cellular phone or PDA, and not with many other types of portable electronic devices.
To alleviate some of these concerns, PDAs and cell phones have been introduced with expansion slots for receiving plug-in GPS receiver modules. The plug-in modules may be inserted into the PDA or phone whenever GPS functions are desired and then removed when not in use. Unfortunately, such plug-in GPS receiver modules are also cumbersome because they require the user to handle and connect two separate devices. Moreover, plug-in GPS receiver modules are not as accurate in determining geographic positioning as dedicated GPS receivers. Another limitation of such plug-in GPS receiver modules is that they are currently designed only for use with PDAs and cellular phones, and not with many other types of portable electronic devices. Moreover, use of these plug-in modules prevents the use of other types of plug-in modules such as expansion memory cards.
Therefore, a need exists for a system and/or method for providing GPS functionalities to portable electronic devices without using expensive and complicated combined units and without requiring the use of plug-in GPS receiver modules.